Tamhankar discloses in U.S. Pat. No. 4,713,224 a one-step process for purifying an inert gas by contacting the inert gas including minute quantities of an impurity selected from the group consisting of CO, CO2, O2, H2, H2O and mixtures thereof with a particulate material comprised of nickel in an amount of at least about 5% by weight as elemental nickel distributed over an effective area of surface, typically from about 100 to 200 m2/g, thereby forming an inert gas having less than 1 ppm and preferably less than 0.1 ppm of any such impurity.
Carrea discloses in U.S. Pat. No. 5,902,561 a two-stage method for removal of impurities such as carbon monoxide, carbon dioxide, oxygen, water, hydrogen, and methane from inert gases at ambient temperature (0° C. to 60° C.). In the first stage, the inert gas is contacted with a nickel catalyst, and in the second stage the inert gas is passed over a getter alloy. Purified gas exiting the second stage of the purifier contains less than one part per billion (ppb) levels of the impurities. The nickel catalyst and getter alloy are initially activated at elevated temperature. The catalyst and getter may be reactivated by heating and purging, and hydrogen previously removed from the impure gas can be used in the reactivation process. Carrea also discloses a purifier with 3 zones where the first zone is particulate nickel, the second purifier zone is a molecular sieve, and the third zone is a getter material.
Shimada in U.S. Pat. No. 5,470,555 discloses a process for purification of organometallic compounds containing impurities by bringing the compound into contact with a catalyst comprising a copper or nickel component as the essential ingredient to remove oxygen contained in an organometallic compound. According to Shimada, the process is capable removal of oxygen in an organometallic compound to as low as 0.1 ppm and further to an ultra-low concentration of 0.01 ppm. Shimada also discloses that it is possible to combine the process of removing oxygen using a catalyst with a process of removing moisture by the use of a synthetic zeolite, etc. according to the demand.
Tako in JP Pub. No. 59-107910 discloses obtaining argon by purification while reducing the cost of operation and the load of maintenance and control by bringing argon into contact with 4A type molecular sieves at a specified temperature and with a metallic getter at a specified temperature, and by further bringing the argon into contact with 5A type molecular sieves under a specified pressure. For example, argon is passed through 4A or 5A type molecular sieves at room temperature or greater than 0° C. to remove chiefly H2O or CO2, and it is passed through a column packed with metallic copper or nickel heated to 150-300° C. to remove H2 or CO. The argon is further passed through 5A type molecular sieves under 5-25 atm pressure.